Kouhei Sutou created ARROW-486: ---------------------------------- Summary: [C++] arrow::io::MemoryMappedFile can't be casted to arrow::io::FileInterface Key: ARROW-486 URL: https://issues.apache.org/jira/browse/ARROW-486 Project: Apache Arrow Issue Type: Bug Components: C++ Affects Versions: 0.2.0 Environment: Linux Reporter: Kouhei Sutou
arrow::io::ReadWriteFileInterface inheritances arrow::io::FileInterface as diamond style via: * ReadableFileInterface -> InputStream -> FileInterface * WriteableFileInterface -> OutputStream -> FileInterface If we have diamond inheritance, we can't cast subclasses of arrow::io::ReadWriteFileInterface such as arrow::io::MemoryMappedFile to arrow::io::FileInterface. C++: #include <arrow/io/file.h> int main(void) { std::shared_ptr<arrow::io::MemoryMappedFile> memory_mapped_file; std::shared_ptr<arrow::io::FileInterface> file = memory_mapped_file; return 0; } Build result: a.cc: In function 'int main()': a.cc:8:52: error: conversion from 'std::shared_ptr<arrow::io::MemoryMappedFile>' to non-scalar type 'std::shared_ptr<arrow::io::FileInterface>' requested std::shared_ptr<arrow::io::FileInterface> file = memory_mapped_file; ^~~~~~~~~~~~~~~~~~ We can resolve it by using virtual inheritance. -- This message was sent by Atlassian JIRA (v6.3.4#6332)